A horizontally-driven vibration body disclosed in Patent Document 1 includes a pair of end covers for closing the axial opposite openings of a cylindrical case made of a magnetic material and for holding the opposite ends of a fixed shaft made of a magnetic material, a cylindrical coil fixed to the inner circumferential surface of the cylindrical case and wound in one direction, a radially-magnetized cylindrical permanent magnet magnetically coupled with the cylindrical coil through an outer circumferential air gap, a pair of radial bearings held at the axial opposite ends of the cylindrical permanent magnet and axially slidably fitted to the fixed shaft, and a pair of springs interposed between the end covers and the axial opposite ends of the cylindrical permanent magnet. If an alternating current is supplied to the cylindrical coil, magnetic fluxes flow through the cylindrical coil existing between the outer circumferential surface of the cylindrical permanent magnet and the cylindrical case. Thus, an alternating axial Lorentz force is generated in the cylindrical permanent magnet as a drive member. The cylindrical permanent magnet is alternately driven to the left and the right in the horizontal direction (axial direction), consequently generating linear reciprocating vibration.
Patent Document 1: Japanese Patent Application Publication No. 2003-93968 (FIG. 1)